Symfony2：如何在表单（查询构建器）中使用左连接和 isnull？

Question

I have a problem with a filter function for which I am using two tables. The first ‚eventcheckin-table' is used for checking in the guests via booking-ID for a certain event. Therfore it should also verify if the ID is already checked in. The ID´s which aren´t yet checked in shall be available as an option in the ‚Entity' field. This problem I tried to solve in the following way:

SELECT booking.booking_id FROM booking LEFT JOIN event_checkin ON  `event_checkin.booking_booking_id = booking.booking_id WHERE` event_checkin.booking_booking_id IS NULL

It works fine.

My solution for the Symfony2 Form Builder is

->add('bookingBooking', EntityType::class, array (
                                'class' => 'AppBundle:Booking',
                                'query_builder' => function (EntityRepository $er) {
                                 return $er->createQueryBuilder('b')
                                 ->leftjoin('AppBundle:EventCheckin', 'e', 'with', 'e.bookingBooking = b.Id')    
                                 ->expr()->isNull('e.bookingbooking');
                                },
                                'label' => 'Booking-ID: * ',
                                ))

Symfony displays this message

Expected argument of type "Doctrine\\ORM\\QueryBuilder", "string" given

How can I solve this problem?

Thanks for your help. ;)

Answer 1

As i think, you can use andWhere statement like :

$er->createQueryBuilder('b')
   ->leftjoin('AppBundle:EventCheckin', 'e', 'with', 'e.bookingBooking = b.Id')
   ->andWhere('e.bookingbooking is null');

Or

$qb = $er->createQueryBuilder('b');

$qb->leftjoin('AppBundle:EventCheckin', 'e', 'with', 'e.bookingBooking = b.Id')
   ->add('where', $qb->expr()->isNull('e.bookingBooking'));

return $qb;

Inspired on this .